US7403249B2 - Liquid crystal display - Google Patents

Liquid crystal display Download PDF

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Publication number
US7403249B2
US7403249B2 US11/135,990 US13599005A US7403249B2 US 7403249 B2 US7403249 B2 US 7403249B2 US 13599005 A US13599005 A US 13599005A US 7403249 B2 US7403249 B2 US 7403249B2
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Prior art keywords
liquid crystal
alignment layers
solvent
crystal layer
lcd
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US11/135,990
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US20060170852A1 (en
Inventor
Chul Hwan Lee
Kyung Ha Lee
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Hydis Technologies Co Ltd
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Boe Hydis Technology Co Ltd
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Assigned to BOE HYDIS TECHNOLOGY CO., LTD. reassignment BOE HYDIS TECHNOLOGY CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LEE, CHUL HWAN, LEE, KYUNG HA
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    • A—HUMAN NECESSITIES
    • A45—HAND OR TRAVELLING ARTICLES
    • A45D—HAIRDRESSING OR SHAVING EQUIPMENT; EQUIPMENT FOR COSMETICS OR COSMETIC TREATMENTS, e.g. FOR MANICURING OR PEDICURING
    • A45D8/00—Hair-holding devices; Accessories therefor
    • A45D8/36—Hair straps; Hair rings
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G02F1/133711—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by organic films, e.g. polymeric films
    • A—HUMAN NECESSITIES
    • A45—HAND OR TRAVELLING ARTICLES
    • A45D—HAIRDRESSING OR SHAVING EQUIPMENT; EQUIPMENT FOR COSMETICS OR COSMETIC TREATMENTS, e.g. FOR MANICURING OR PEDICURING
    • A45D8/00—Hair-holding devices; Accessories therefor
    • A45D8/002—Accessories therefor
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1343—Electrodes
    • G02F1/134309—Electrodes characterised by their geometrical arrangement
    • G02F1/134363—Electrodes characterised by their geometrical arrangement for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]

Definitions

  • the present invention relates to a liquid crystal display (LCD), and more particularly to an LCD with improved image retention for increased reliability and screen quality.
  • LCD liquid crystal display
  • FFS-mode LCD A fringe field switching mode (hereinafter, referred to as FFS-mode) LCD has been proposed to improve the low aperture ratio and transmittance of an in-plane switching mode (hereinafter, referred to as IPS-mode) LCD, as disclosed in Korean Patent Application No. 98-9243.
  • IPS-mode in-plane switching mode
  • the FFS-mode LCD has counter and pixel electrodes made of a transparent conductor for higher aperture ratio and transmittance than the IPS-mode LCD. Furthermore, the gap between the counter and pixel electrodes is smaller than that between upper and lower substrates to form a fringe field between the counter and pixel electrodes. As a result, all liquid crystal molecules are actuated, including those positioned on top of the electrodes, for improved transmittance.
  • FIG. 1 is a sectional view thereof.
  • a black matrix layer 2 is formed on an upper substrate 1 to interrupt transmission of light and a color filter layer 3 including red, green, and blue is formed thereon.
  • An over-coating layer 4 is formed on the black matrix layer 2 and the color filter layer 3 .
  • a common electrode 12 is formed on a lower substrate 11 in a plate shape, and a gate insulation layer 13 is formed on the resulting substrate including the common electrode 12 .
  • a data line 14 is formed on the gate insulation layer 13 , and a protective layer 15 is formed on the resulting substrate including the data line 14 .
  • a pixel electrode 16 is formed on the protective layer 15 in a slit shape. Alignment layers 5 and 17 are formed between the upper substrate 1 and a liquid crystal layer 18 and between the lower substrate 11 and the liquid crystal layer 18 , respectively, to determine the initial arrangement of liquid crystals.
  • the conventional FFS-mode LCD however, has no electrode formed on the upper substrate, in contrast to a TN-mode LCD. Since the black matrix layer and the over-coating layer are made of a material having very high specific resistance, furthermore, image retention is very likely to occur. Particularly, the FFS-mode LCD has a larger capacitor than the TN-mode LCD. The resulting adsorption of impurity ions and the influence of the remaining DC components generate severe image retention.
  • An alignment agent for forming the alignment layers includes a polymer compound and a solvent for dissolving the polymer compound to improve coating characteristics.
  • the polymer compound is used to align the liquid crystals in a predetermined direction.
  • the solvent is a liquid-state material having low viscosity for easy application of the polymer compound and is used to retain the alignment agent.
  • the alignment agent including the polymer compound and the solvent, has large specific resistance during application and increases the capacitance inside the LCD. This results in the image retention of the LCD.
  • the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a LCD with improved image retention for increased reliability and screen quality.
  • an LCD including lower and upper substrates provided with predetermined patterns, respectively, and positioned to face each other with a predetermined distance; a liquid crystal layer interposed between the lower and upper substrates; and alignment layers positioned between the lower substrate and the liquid crystal layer and the upper substrate and the liquid crystal layer, respectively, to determine the initial arrangement of liquid crystals, wherein the alignment layers have bubbles formed therein to reduce the capacitance generated by the alignment layers and the difference in level of the lower substrate for improved image retention.
  • the alignment layers include a polymer compound for arranging the liquid crystals in a predetermined direction; a first solvent having low viscosity, low specific weight, and high volatility at a temperature of 70-80° C.; and a second solvent having high specific weight and high volatility at a temperature of 100° C. or higher.
  • FIG. 1 is a sectional view showing a conventional FFS-mode LCD
  • FIG. 2 is a sectional view showing an LCD, after precure, according to an embodiment of the present invention.
  • FIG. 3 is a sectional view showing an LCD, after maincure, according to an embodiment of the present invention.
  • FIG. 2 is a sectional view showing an LCD, after precure, according to an embodiment of the present invention
  • FIG. 3 is a sectional view showing an LCD, after maincure, according to an embodiment of the present invention.
  • a black matrix layer 22 is formed on an upper substrate 21 to interrupt transmission of light and a color filter layer 23 including red, green, and blue is formed thereon.
  • An over-coating layer 24 is formed on the black matrix layer 22 and the color filter layer 23 .
  • a common electrode 32 is formed on a lower substrate 31 in a plate shape, and a gate insulation layer 33 is formed on the resulting substrate including the common electrode 32 .
  • a data line 34 is formed on the gate insulation layer 33 , and a protective layer 35 is formed on the resulting substrate including the data line 34 .
  • a pixel electrode 36 is formed on the protective layer 35 in a slit shape.
  • Alignment layers 25 and 37 are formed between the upper substrate 21 and a liquid crystal layer 38 and between the lower substrate 31 and the liquid crystal layer 38 , respectively, to determine the initial arrangement of liquid crystals.
  • the resulting substrate including the pixel electrode 36 is coated with an alignment agent to form an alignment layer 37 on the lower substrate 31 .
  • the alignment agent includes a polymer compound for arranging liquid crystals in a predetermined direction, a first solvent having low viscosity, low specific weight, and high volatility at a temperature of 70-80° C., and a second solvent having high specific weight and high volatility at a temperature of 100° C. or higher.
  • the first solvent rapidly volatilizes from the surface layer of the alignment agent, while the surface is cured, to form a first alignment layer 37 a having a smooth surface.
  • the second solvent does not volatilize, due to high specific weight, and is distributed inside a second alignment layer 37 b of the lower substrate 31 in a liquid state.
  • the lower substrate 31 coated with the alignment agent After being heated at a temperature of 70-80° C., the lower substrate 31 coated with the alignment agent is subject to heat treatment at an elevated temperature of 100° C. or higher for imidization through recombination of the polymer compound, as shown in FIG. 3 , so that the second solvent volatilizes together with imidization of the alignment agent.
  • the second solvent cannot be discharged from the surface of the alignment agent and forms bubbles A therein.
  • air layer is formed inside the second alignment layer 37 b . This reduces the capacitance of the alignment layers.
  • the first solvent having low viscosity and low specific weight When the alignment agent is applied to the lower substrate, furthermore, the first solvent having low viscosity and low specific weight generates a difference in the amount of application between a high stepped-portion and a low stepped-portion. Such a difference in the amount of application varies the amount of bubbles generated by the second solvent and adjusts the thickness of the alignment layers according to the patterns of the lower substrate. As such, the difference in level of the patterns formed on the lower substrate is compensated for and alignment layers having excellent flatness are obtained.
  • the LCD according to the present invention has bubbles formed inside the alignment layers for reduced capacitance thereof.
  • the thickness of the alignment layers is adjusted according to the patterns of the lower substrate. This compensates for the difference in level of the patterns of the lower substrate and provides alignment layers having excellent flatness.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)
US11/135,990 2005-01-29 2005-05-24 Liquid crystal display Active 2025-12-29 US7403249B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1020050008365A KR100707030B1 (ko) 2005-01-29 2005-01-29 액정표시장치
KR10-2005-0008365 2005-01-29

Publications (2)

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US20060170852A1 US20060170852A1 (en) 2006-08-03
US7403249B2 true US7403249B2 (en) 2008-07-22

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US11/135,990 Active 2025-12-29 US7403249B2 (en) 2005-01-29 2005-05-24 Liquid crystal display

Country Status (5)

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US (1) US7403249B2 (ko)
JP (1) JP4332745B2 (ko)
KR (1) KR100707030B1 (ko)
CN (1) CN1811567B (ko)
TW (1) TW200627005A (ko)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101348760B1 (ko) 2007-01-20 2014-01-08 삼성디스플레이 주식회사 이온 포착 구조를 구비한 액정표시패널 및 이를 포함한액정표시장치
KR20170052742A (ko) * 2015-11-03 2017-05-15 삼성디스플레이 주식회사 액정 표시 장치 및 그 제조 방법

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR970004881B1 (ko) 1991-07-08 1997-04-08 알프스 덴기 가부시기가이샤 액정의 배향막, 그 제조방법, 액정소자 및 그 제조방법
US5786041A (en) * 1995-06-07 1998-07-28 International Business Machines Corporation Alignment film, a method for producing the alignment film and a liquid crystal display device using the alignment film

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002098810A (ja) * 2000-09-21 2002-04-05 Keiwa Inc 異方性拡散シート、この異方性拡散シートの製造方法及びこの異方性拡散シートを用いたバックライトユニット
CN1475814A (zh) * 2002-08-16 2004-02-18 惠和株式会社 反射薄片以及使用该薄片的背光组件
US7105211B2 (en) * 2002-05-23 2006-09-12 Nissan Chemical Industries, Ltd. Liquid crystal aligning agent, liquid crystal aligning films, and liquid crystal display devices

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR970004881B1 (ko) 1991-07-08 1997-04-08 알프스 덴기 가부시기가이샤 액정의 배향막, 그 제조방법, 액정소자 및 그 제조방법
US5786041A (en) * 1995-06-07 1998-07-28 International Business Machines Corporation Alignment film, a method for producing the alignment film and a liquid crystal display device using the alignment film

Also Published As

Publication number Publication date
JP2006209075A (ja) 2006-08-10
CN1811567B (zh) 2012-03-14
JP4332745B2 (ja) 2009-09-16
CN1811567A (zh) 2006-08-02
KR100707030B1 (ko) 2007-04-11
US20060170852A1 (en) 2006-08-03
KR20060087327A (ko) 2006-08-02
TW200627005A (en) 2006-08-01
TWI305586B (ko) 2009-01-21

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